Recent Perspectives and Crucial Challenges on Unitized Regenerative Fuel Cell (URFC)

Abstract

Renewable sources of energy are becoming increasingly popular in recent years. The idea of using alternative energy that utilizes renewable sources is to slowly replace our dependence on fossil fuels. Conventional fossil fuels are not viable due to the fact that they are predominantly unsustainable over the long run. Furthermore, pollution will be reduced through the use of cleaner and more environmentally friendly renewable energy. Polymer electrolyte membrane fuel cell (PEMFC), which utilizes hydrogen as fuel, has a high potential as an alternative power generator. The unitized regenerative fuel cell (URFC) is a type of PEMFC that can perform both in charge mode (as a fuel cell) and discharge mode (as an electrolyzer). This review looks into the recent researches on the structure and different components of the URFC. In particular, emphasis is placed on bifunctional electrodes. Recent development in URFC research has produced a more stable bifunctional electrode with improved energy efficiency and overall stability and durability. Various works have been carried out to replace Pt as the electrocatalyst, including the use of graphene as a low cost non-metal graphene-based electrocatalyst. Electrocatalyst support also plays an important role in increasing conductivity while reducing the catalyst resistance to corrosion. The technological challenges and limitations of the URFC system are also discussed in this review.

Development of a Bifunctional Ti-Based Gas Diffusion Electrode for ORR and OER by One- and Two-Step Pt-Ir Electrodeposition

“…To further characterize the OER activity of the electrode, LSV measurements ( Figure 9 a) were performed and analyzed regarding the mass activity (MA) and kinetic parameters. LSV measurements for the Ti-based single Pt electrodes were not performed due to the poor OER performance of Pt-catalysts discussed in the literature [ 10 , 22 , 66 ].…”

“…High membrane electrode assembly (MEA) costs represent a bottleneck for upscaling PEM-based hydrogen technology [ 18 , 19 , 20 , 21 ]. Combining both hydrogen technologies, the UR-PEMFC offers the possibility of cost savings due to the use of one electrochemical cell consisting of electrodes with bifunctional catalyst layers [ 10 , 22 ]. Further cost reduction is achievable by reduction in the noble metal catalyst loading on the electrodes for PEM-based hydrogen energy systems [ 23 , 24 , 25 , 26 , 27 ].…”

Solutions to the water flooding problem for unitized regenerative fuel cells: status and perspectives

“…Despite the continuing research into URFC technology, the round-trip efficiency of URFCs is still lower than that of secondary batteries, 26,42 mainly due to the water issues that occur when switching from fuel cell to electrolysis mode and vice versa. 43 Other complications include the effects of water ooding, water starvation, and water transport between the components during fuel cell and electrolysis operation. 44…”

“…51 Accordingly, water management is a delicate task, as either an excess or deciency of water can adversely impact the performance and lifetime of the URFC. 43 Effective water management to maintain an appropriate balance between membrane humidity and the removal of the excess water produced in fuel cell mode is one of the most important issues in URFC design.…”

A review of alkaline solid polymer membrane in the application of AEM electrolyzer: Materials and characterization

“…Acid rain production can occur, resulting in disruptions to habitats such as water pollution and damage to animals and crops. Therefore, the alternative energy resources approach is desperately needed to reduce fossil fuels' use to mitigate the environmental crisis 5,6 …”